The present invention relates generally to chucks for use with drills or with electric or pneumatic power drivers. More particularly, the present invention relates to a chuck of the keyless type which may be tightened or loosened by hand or by actuation of the driver motor.
Both hand and electric or pneumatic tool drivers are well known. Although twist drills are the most common tools used with such drivers, the tools may also comprise screwdrivers, nut drivers, burrs, mounted grinding stones, and other cutting or abrading tools. Since the tools may have shanks of varying diameter or may have a polygonal cross-section, the device is usually provided with a chuck that is adjustable over a relatively wide range. The chuck may be attached to the driver by a threaded or tapered bore.
A wide variety of chucks have been developed in the art. In one form of chuck, three jaws spaced circumferentially approximately 120xc2x0 apart from each other are constrained by angularly disposed passageways in a body attached to the drive shaft. The chuck is configured so that rotation of the body in one direction with respect to a constrained nut forces the jaws into or away from gripping relationship with a tool shank. Such a chuck may be keyless if it can be tightened or loosened by manual rotation. An example of such chuck is disclosed in U.S. Pat. No. 5,125,673, commonly assigned to the present assignee and the entire disclosure of which is incorporated herein by this reference.
The present invention recognizes and addresses disadvantages of prior art construction and methods.
Accordingly, it is an object of the present invention to provide an improved chuck for use with a power driver.
This and other objects are achieved by a chuck for use with a power driver having a rotatable spindle. The chuck includes a generally cylindrical body defining a tail section configured to rotate with the spindle of the power driver and a nose section having an axial bore formed therein. A plurality of jaws are in communication with the axial bore. A driving disk is rotatably mounted about the body in driving engagement with the jaws so that rotation of the driving disk with respect to the body moves the jaws toward or away from the axis of the axial bore, depending on the direction of rotation. A bearing is disposed between the driving disk and the body so that rearward axial force is transferred from the driving disk to the body through the bearing when the jaws close onto a tool received in the axial bore. The bearing includes a first race, a second race and a plurality of bearing elements disposed between the first race and the second race. The first race defines a plurality of recesses therein. One of the second race and the bearing elements is disposed in communication with the first race so that, when the jaws close onto the tool and the first and second races rotate relative to each other, the one of the second race and the bearing elements engages successive recesses.
In another embodiment, a chuck includes a generally cylindrical body that defines a tail section configured to rotate with the spindle of the power driver and a nose section having an axial bore formed therein. A plurality of jaws are in communication with the axial bore. A driving disk is axially moveably disposed about the body in driving engagement with the jaws so that axial movement of the driving disk with respect to the body moves the jaws toward or away from the axis of the axial bore, depending on the direction of the axial movement. The driving disk defines a threaded outer circumferential surface. A generally cylindrical sleeve is rotatably mounted about the body and defines a threaded inner circumferential surface engaging the threaded outer surface of the driving disk so that relative rotation between the driving disk and the sleeve moves the driving disk axially with respect to the body. A bearing is disposed between the driving disk and the sleeve so that rearward axial force is transferred from the sleeve to the body through the bearing when the jaws close onto a tool received in the axial bore. The bearing includes a first race, a second race and a plurality of bearing elements disposed between the first race and the second race. The first race defines a plurality of recesses. One of the first race and the bearing elements is disposed in communication with the first race so that, when the jaws close onto the tool and the first race and the second race rotate relative to each other, the one of the second race and the bearing elements engages successive recesses.